First and foremost, thank you for making this mod!
I absolutely love it and have been using it in my private modpack since it first became available.

Now on to the issue.
The undead boars seem to be able to attack through single layer solid blocks.
What I mean with that, is that they attack through 1 block thick walls both vertically and horizontally.
I experienced this while playing in singleplayer and hiding underground until day time on the first day, using half slabs at the front so I can see the sunrise. The hog spotted me and tried to attack me, whereas I retreated further back into the self made dirt hole. The top layer was only a 1 block thick layer of dirt.
The hog continued to be able to hit me no matter where I stood.
Then tested it in a creative enviroment and got it to confirm.
2 block thick walls and floors seem to prevent this.

Edit: I should probably mention I'm using the latest beta version that's been released yesterday.